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M1.7 Earthquake near Portage Creek, United States — 20 August 2025, 01:42 UTC

A micro earthquake of magnitude 1.7 was recorded near Portage Creek, United States on , with an epicentre 22 km east-southeast of Portage Creek, at a focal depth of 220.7 km. It ranked as the 1592nd strongest of 7314 earthquakes recorded in the United States in the preceding 30 days.

1.7 Micro

Time (UTC): 2025-08-20 01:42:12

Time (your timezone): —

Magnitude: 1.7 (micro)

Focal depth: 220.7 km (intermediate)

Epicentre: 58.8620, -157.3290

Location: 22 km ESE of Portage Creek, Alaska

Country: United States

USGS link to NOAA tsunami information: Not linked

Review status: Automatic

Source: USGS event page

How strong was this earthquake?

Micro earthquakes are almost never felt at the surface and are recorded only by seismographs.

A magnitude 1.7 earthquake radiates roughly 5.4 kg of TNT equivalent in seismic energy.

The USGS assigns this earthquake a significance score of 44, which is below the USGS threshold of more than 600 for its significant-earthquake list. The ranking combines magnitude with available Did You Feel It responses and PAGER alert level; it is not a direct measurement of damage.

What the magnitude scale actually measures →

When it happened locally

That is about 15:12 local solar time at the epicentre, during the afternoon.

This event was deeper than 100% of the 156,299 earthquakes recorded in the United States in our catalogue and stronger than 68% of them.

Where was the epicentre?

The epicentre was located at 58.8620, -157.3290 — 22 km east-southeast of Portage Creek. The closest other recorded event was a magnitude 0.9 earthquake 91 km southeast of here on 23 August 2026.

The nearest other settlements in our records are Clarks Point (86 km west-southwest), Aleknagik (131 km west-northwest), Egegik (133 km south-southeast) and Chuathbaluk (211 km north-northwest).

Why the 221 km depth matters

At 221 km this was an intermediate-depth earthquake. Energy from events at this depth spreads out before it reaches the surface, which usually means weaker shaking near the epicentre than a shallow quake of the same magnitude, but shaking felt across a wider area.

This catalogue does not ingest eyewitness responses, so it cannot confirm where this earthquake was felt. Based on magnitude alone, events this small are usually detected by instruments rather than people. Its intermediate depth normally reduces peak shaking near the epicentre compared with a shallow event of the same magnitude.

Read more on how focal depth changes what you feel →

What does the tsunami information flag mean?

The USGS record does not carry a link to NOAA tsunami information. That field is not an all-clear and does not state whether a tsunami occurred. In this case, a damaging tsunami would be less likely because at M1.7 it falls below the magnitude 6.5 threshold that generally applies before a submarine earthquake displaces enough water to generate a damaging tsunami; its 221 km focal depth is too great to deform the sea floor significantly; it occurred inland rather than beneath the sea floor. For an active coastal alert, use tsunami.gov or your local warning authority.

How earthquakes generate tsunamis, and what the alert levels mean →

Aftershocks and local seismic history

5 further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event, the largest of them magnitude 2.1.

3 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.1 event near Egegik on 01 April 2025. This M1.7 event released about 125,893 times less energy than that event.

52 earthquakes have been recorded within 100 km of this epicentre in the past year, 11 of them in the past 30 days.

How long aftershock sequences last, and how large they get →

Where this event sits in the record

This earthquake is part of the August 2025 worldwide record, and of earthquakes in the United States during August 2025. Browse the full monthly archive to compare periods.

Nearest recorded earthquakes to this epicentre

Other recent earthquakes in the United States

All recorded earthquakes in the United States →

Other magnitude 1 earthquakes worldwide

Questions about this earthquake

How strong was the earthquake near Portage Creek?

It measured magnitude 1.7 — a micro earthquake. A magnitude 1.7 earthquake radiates roughly 5.4 kg of TNT equivalent in seismic energy.

How deep was the earthquake near Portage Creek?

The focus was 221 km below the surface, which counts as intermediate.

Was the Portage Creek earthquake felt at the surface?

At magnitude 1.7 and a focal depth of 221 km, the depth spreads the energy out, so shaking is weaker overhead but reaches further.

When did the earthquake near Portage Creek happen?

20 August 2025 at 01:42 UTC.

Was there a tsunami?

No. The USGS record carries no tsunami-information link for this event.

Have there been aftershocks?

5 further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event, the largest of them magnitude 2.1.

How often do earthquakes happen near Portage Creek?

3 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.1 event near Egegik on 01 April 2025. This M1.7 event released about 125,893 times less energy than that event.